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Re: *Jeholornis* (Archaeopterygiformes: Rahonavidae)??



> (Just for the record... Archaeopterygiformes has never been defined, and
> Rahonavidae has AFAIK never been published; [snip] The subject line just
sounds impressive that way.)
>
It does ;)
>
> I think it's hardly similar at all. The dentary is long and low, instead
of
> very high and short as in oviraptorosaurs (even *Incisivosaurus*, the
least
> extreme example).
>
Caenagnathids show a long and low dentary, should we stop considering those
Ovi's? Second, a slender dentary is in line with the dentary observed in
Archaeopteryx, impying it's connecting position between Archie and Ovi's.
>
> This <a reduced maxilla> sounds better. But it could be convergence
because of selection for a
> strong bite in the front of the jaw... and it's also present in all
avebrevicaudans with described skulls.
>
Agreed, but Ovi's show them in their skulls and the feature here should have
had to come from somewhere. The counter-argument is not great, but this is
because I don't see the connection between the two, how come one is related
to the other?
>
> Evolves easily when bite strength is needed more than intraramal mobility.
> I'm sure your own dentary symphysis is fused. :-)
>
Last time I checked it did ;) But this is a single character, and lucky for
us, cladistic analyses do not base their results on single characters, or
else we will end up with the Ovi's in a strange phylogenetic twist...  It's
the total of all characters used for the genera and these combined
characters are what will create the result that will come out of the study.
>
> Assuming the jugal of *Jeholornis* is what the authors identify as such,
it
> is curved the opposite way of that of *Incisivosaurus*.
>
The distal end of the jugal is broken of about a centimer from the jugal
process, so the curvature is not completely observed, but there is a small
indication. The indicication is to be found just right of the quadrate which
is the remainder of the jugal of what is preserved. As you will notice,
there is a curvature seen at it's distal end, a feature, as you have
mentioned, is seen Incisivosaurus. The area you pointed out is indeed curved
the opposite way of that seen in Incisivosaurus, but this is exactly the
opposite site I was talking about. This part of the jugal does indeed show
little similarity to that seen of I. , but does show a great deal of
similarity to the condition seen in Archaeopteryx for example, and this is
in correlation with that the two are closely related, as said before,
something of which I have no doubt.
>
> To the contrary, *Jeholornis* is a bit more opisthopubic than both
> *Archaeopteryx* and *Rahonavis*.
>
You're right, sorry about that.
>
> *Jeholornis* shares with *Rahonavis* (and Ornithothoraces), but not
> *Archaeopteryx* (or basal Avebrevicauda), the joint between scapula and
> coracoid. The coracoid is longer than in *Archaeopteryx* and *Sapeornis*.
> Apparently the fibula doesn't reach the calcaneum anymore as in
*Rahonavis*
> and Pygostylia, but again unlike *Archaeopteryx* and *Sapeornis*.
>
Meaning?
>
> The text mentions a "hypertrophied second ungual" in the foot, I can't
tell from the
> photo.
>
Maybe because it is not there, they have been wrong about calling the tail
Dromeosaurid-like before and they could easily make the same mistake again
with the unguals. Not that the paper is bad, but just in the details it has
it's flaws. When looking at the unguals, you'll notice that there are 8
unguals the preserved, the total count, but only two of them are only
slightly larger than the other six, this could imply that, as usually found,
the claw on the third digit was larger than the remaining. This is just
speculation, because the feet are completely disarticulated, so saying/
writing that the second ungual is hypertrophied is based on their guesses
and does not have to be the correct condition.
>
> > This has been my two cents...
>
> You're underpaid.
>
Is this a compliment? ;)

Cheers,

Rutger Jansma